Redwood is the brand name of a nitric oxide-boosting supplement produced by UMZU that promises to improve circulation, lower blood pressure and treat varicose veins.
Redwood supplements include a proprietary mix of four natural ingredients meant to promote the production of nitric oxide in the body. While there is some scientific support around the benefits of these ingredients, research on the overall effectiveness of nitric oxide supplementation is mixed. Read on to determine whether you should consider adding this supplement to your nutritional plan.
What Is Nitric Oxide?
Nitric oxide is a gas that increases blood flow, and it naturally occurs in your body. Nitric oxide supplements are meant to increase your body's production of the gas, with the idea being that the resulting increased blood flow will help enhance your athletic performance.
Nitric oxide is a vasodilator, explains Colette Raymond, a registered dietitian based in Colorado Springs, Colorado. "It relaxes the muscles of the inner walls of our blood vessels, allowing for increased circulation," she says. This helps blood, nutrients and oxygen travel more efficiently to organs and muscles.
Boost Nitric Oxide Naturally
"Eating a diet rich in leafy greens and fresh fruits, especially watermelon, beets and beet juice, can make it easier for your body to make nitric oxide," Raymond says. "Getting regular exercise and spending time outside in the sun can also boost nitric oxide production."
Read more: Why Are Beets Good for You?
As you age, however, "your body may not be as good at converting dietary nitrates into nitric oxide," she notes, which is when some people may turn to supplements.
Still, dietary interventions— especially featuring such nitrate-rich foods as leafy greens and beetroot juice — can have a positive effect on athletic performance. In fact, an August 2018 paper in the Annual Review of Nutrition linked the consumption of these foods with improved sprint performance, muscle power and muscle efficiency.
What Are Nitric Oxide Supplements?
Nitric oxide supplements don't contain nitric oxide; instead, they're made from ingredients that are thought to increase your body's nitric oxide production, such as the amino acids arginine and citrulline, Raymond says.
Read more: Nitric Oxide Supplement Warnings
Redwood supplements do not contain amino acids. These pills are made up of a unique set of ingredients designed to drive nitric oxide production: vitamin C, garlic bulb extract, pine bark extract and horse chestnut fruit extract.
The supplement industry is notorious for a lack of regulation. Unlike prescription drugs or over-the-counter medications, herbal supplements don’t have to be tested or approved by the U.S. Food and Drug Administration before hitting the market. If you decide to take Redwood supplements or any other nitric oxide booster, stick to the recommended dosage and be sure to carefully monitor yourself for any adverse side effects.
Nitric oxide supplements, including Redwood, supposedly help improve blood flow, leading to better muscle pump, improved endurance and faster recovery from workouts. Research on these benefits is mixed, however, as is reported in a February 2012 review published in Sports Medicine. Many studies suggest that nitric oxide production does enhance oxygen and nutrient delivery to active muscles, while others find no positive effect.
However, pine bark extract, an ingredient in Redwood supplements, seems to improve athletic stamina. According to a study published in December 2013 in The Journal of Sports Medicine and Physical Fitness, athletes training for a physical fitness test or triathlon seemed to perform better when they took regular doses (either 100 or 150 milligrams per day) of pine bark extract in the eight weeks leading up to the test or competition.
The improved blood flow and wider blood vessels produced by nitric oxide can help lower blood pressure levels. A study published in the January 2015 issue of the Journal of Cardiovascular Pharmacology & Therapeutics found that oral supplementation with nitric oxide appeared to lower blood pressure in patients with prehypertension and could offer benefits for long-term cardiovascular health protection as well.
There's also evidence that garlic bulb extract, which is one of Redwood's ingredients, might affect blood pressure and related disorders. Research published in Molecules in June 2016 affirms that the extract shows promise as an effective natural treatment for hypertension, hypercholesterolemia and even type 2 diabetes.
Read more: What Is Normal for Blood Pressure?
Redwood supplements claim to prevent cardiovascular disease by boosting nitric oxide. Indeed, vitamin C, which is an ingredient in the supplements, may help heart health. Vitamin C deficiency is associated with a higher risk of mortality from cardiovascular disease, reports a paper in the August 2016 issue of the International Journal of Molecular Sciences.
The study notes that vitamin C supplementation can improve endothelial function, which refers to the interior lining of the heart and blood vessels. However, it's not clear that vitamin C supplementation actually reduces mortality from cardiovascular disease or the risk of developing heart disease.
Redwood supplements also claim to reduce the inflammation and swelling associated with varicose veins by improving blood flow and strengthening veins and blood vessels.
Research published in Molecules in June 2016 does list horse chestnut, an ingredient in Redwood supplements, as a natural solution for venous insufficiency and varicose veins. Taking horse chestnut, even for a short time, can be as effective as wearing compression stockings in mitigating the pain and swelling of varicose veins, notes the National Center for Complementary and Integrative Health.
The pine bark extract in Redwood supplements has also been found effective in reducing venous insufficiency, reports Medline Plus, a website run by the National Institutes of Health and produced by the National Library of Medicine. Oral supplementation with the compound seems to reduce leg pain as well as fluid retention.
Research indicates that nitric oxide production plays a role in men's erectile performance. The idea is that improved vascularity can resolve erectile dysfunction (ED) and make erections stronger and harder.
The company behind Redwood claims ED resolution as one of the supplement's positive benefits. Indeed, the ingredient pycnogenol, or pine bark extract, has been shown in research to have the potential to improve male performance.
Research published in a November 2018 issue of Rejuvenation Research, for example, reports that the compound, when combined with the amino acid l-arginine, restores erectile function in men with erectile dysfunction.
Redwood supplements also claim to improve brain function, which is a possible benefit of pine bark extract. The same study published in Rejuvenation Research showed that the compound has a positive effect on cognitive function in the elderly, and especially spatial memory.
Safety and Potential Side Effects
Raymond notes that you should be cautious when using supplements such as Redwood. Because nitric oxide is a vasodilator, those who suffer from low blood pressure or bleeding disorders should be especially careful. And regardless of your health status, it's always a good idea to speak with your doctor or healthcare provider before adding any supplements to your diet.
There are also several things to keep in mind about Redwood's four ingredients:
Pine bark extract: This compound is considered safe, reports Medline Plus, when taken in doses of 50 to 450 milligrams daily for up to a year. Redwood supplements contain 100 milligrams in each daily dose.
Horse chestnut: This ingredient is also considered generally safe for consumption, reports the National Center for Complementary and Integrative Health. But keep in mind that both pine bark extract and horse chestnut can cause stomach problems, headaches and other such minor side effects.
Vitamin C: The tolerable upper limit of vitamin C is 2,000 milligrams per day, but this is well above the recommended daily amount of 65 to 90 milligrams a day. Redwood supplements contain 1,000 milligrams per dose. Mayo Clinic points out that megadoses of vitamin C may cause stomach upset, headache and insomnia.
Garlic bulb extract: This substance is generally considered safe but can increase blood thinning, which can be an issue for people with bleeding disorders. It may also cause gastrointestinal upset.
- Journal of Cardiovascular Pharmacology & Therapeutics: Effects of an oral nitric oxide supplement on functional capacity and blood pressure in adults with prehypertension
- Molecules: Natural Products to Counteract the Epidemic of Cardiovascular and Metabolic Disorders
- Rejuvenation Research: Pleiotropic Effects of French Maritime Pine Bark Extract to Promote Healthy Aging
- National Center for Complementary and Integrative Health: Horse Chestnut
- International Journal of Molecular Sciences: Vitamin C and Heart Health: A Review Based on Findings from Epidemiologic Studies
- Medline Plus: Maritime Pine
- MayoClinic: Is It Possible to Take Too Much vitamin C?
- Annual Review of Nutrition: Dietary Nitrate and Physical Performance.
- Sports Medicine: The effect of nitric-oxide-related supplements on human performance
- The Journal of Sports Medicine and Physical Fitness: "Evaluation of the effects of supplementation with Pycnogenol® on fitness in normal subjects with the Army Physical Fitness Test and in performances of athletes in the 100-minute triathlon."